How to connect Ubuntu system to mac OS computers on ethernet ЛВС?

I have в помещение network in the house that - Apple computers with Мак ВЫ on it, except the Ubuntu 14.04.3 system I now have on one computer (an Intel Macmini). The mac's connect using either IP addresses I assigned back when I set it up or afp (Apple file protocol) addresses. гm в longtime extensive user of персонал computers, almost entirely Mac's, but гm not в "techie" and don't do code at any level. I like the Ubuntu system but I can't find how to connect the Ubuntu computer with the Mac's for file exchange, и т.д.... Do not want to do it Интернет путь.